The linguistic transition that usually accompanies immigration is often related to a strong sense of split between two places, languages, identities and emotional settings. What happens, then, when people change countries and languages three, four or even five times during childhood and adolescence? In the present study, focusing on Third Culture Kids (TCKs), we collected background information and data on cultural affiliation, identity and emotional expressiveness as linked with language aspects from 54 participants aged 18–30 years. In-depth interviews with eight participants followed. Analyses revealed significant relationships between non-linguistic and language-related factors, and TCKs' sense of identity. Participants used languages to define themselves and others. For many, being multilingual was indeed their identity. Many perceived languages as their roots, without confinement to a geographical location, and the notion of language dominance emerged as very different from that of typical immigrants, including language choice for emotional expressiveness. Women were generally more responsive to differences in cultural interaction in terms of language use and emotional expressiveness. This study is a significant contribution to the evolving literature on this population, and results are discussed in light of psychological theories of language and emotions as well as models of transnationalism.